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* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
* http://www.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
/*
* Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2012, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Lustre is a trademark of Sun Microsystems, Inc.
*
* lustre/include/lustre_lib.h
*
* Basic Lustre library routines.
*/
#ifndef _LUSTRE_LIB_H
#define _LUSTRE_LIB_H
/** \defgroup lib lib
*
* @{
*/
#include <linux/sched/signal.h>
#include <linux/signal.h>
#include <linux/types.h>
#include <linux/libcfs/libcfs.h>
#include <uapi/linux/lustre/lustre_idl.h>
#include <uapi/linux/lustre/lustre_ver.h>
#include <uapi/linux/lustre/lustre_cfg.h>
/* target.c */
struct ptlrpc_request;
struct obd_export;
struct lu_target;
struct l_wait_info;
#include <lustre_ha.h>
#include <lustre_net.h>
#define LI_POISON 0x5a5a5a5a
#if BITS_PER_LONG > 32
# define LL_POISON 0x5a5a5a5a5a5a5a5aL
#else
# define LL_POISON 0x5a5a5a5aL
#endif
#define LP_POISON ((void *)LL_POISON)
int target_pack_pool_reply(struct ptlrpc_request *req);
int do_set_info_async(struct obd_import *imp,
int opcode, int version,
u32 keylen, void *key,
u32 vallen, void *val,
struct ptlrpc_request_set *set);
void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id);
/*
* l_wait_event is a flexible sleeping function, permitting simple caller
* configuration of interrupt and timeout sensitivity along with actions to
* be performed in the event of either exception.
*
* The first form of usage looks like this:
*
* struct l_wait_info lwi = LWI_TIMEOUT_INTR(timeout, timeout_handler,
* intr_handler, callback_data);
* rc = l_wait_event(waitq, condition, &lwi);
*
* l_wait_event() makes the current process wait on 'waitq' until 'condition'
* is TRUE or a "killable" signal (SIGTERM, SIKGILL, SIGINT) is pending. It
* returns 0 to signify 'condition' is TRUE, but if a signal wakes it before
* 'condition' becomes true, it optionally calls the specified 'intr_handler'
* if not NULL, and returns -EINTR.
*
* If a non-zero timeout is specified, signals are ignored until the timeout
* has expired. At this time, if 'timeout_handler' is not NULL it is called.
* If it returns FALSE l_wait_event() continues to wait as described above with
* signals enabled. Otherwise it returns -ETIMEDOUT.
*
* LWI_INTR(intr_handler, callback_data) is shorthand for
* LWI_TIMEOUT_INTR(0, NULL, intr_handler, callback_data)
*
* The second form of usage looks like this:
*
* struct l_wait_info lwi = LWI_TIMEOUT(timeout, timeout_handler);
* rc = l_wait_event(waitq, condition, &lwi);
*
* This form is the same as the first except that it COMPLETELY IGNORES
* SIGNALS. The caller must therefore beware that if 'timeout' is zero, or if
* 'timeout_handler' is not NULL and returns FALSE, then the ONLY thing that
* can unblock the current process is 'condition' becoming TRUE.
*
* Another form of usage is:
* struct l_wait_info lwi = LWI_TIMEOUT_INTERVAL(timeout, interval,
* timeout_handler);
* rc = l_wait_event(waitq, condition, &lwi);
* This is the same as previous case, but condition is checked once every
* 'interval' jiffies (if non-zero).
*
* Subtle synchronization point: this macro does *not* necessary takes
* wait-queue spin-lock before returning, and, hence, following idiom is safe
* ONLY when caller provides some external locking:
*
* Thread1 Thread2
*
* l_wait_event(&obj->wq, ....); (1)
*
* wake_up(&obj->wq): (2)
* spin_lock(&q->lock); (2.1)
* __wake_up_common(q, ...); (2.2)
* spin_unlock(&q->lock, flags); (2.3)
*
* kfree(obj); (3)
*
* As l_wait_event() may "short-cut" execution and return without taking
* wait-queue spin-lock, some additional synchronization is necessary to
* guarantee that step (3) can begin only after (2.3) finishes.
*
* XXX nikita: some ptlrpc daemon threads have races of that sort.
*
*/
static inline int back_to_sleep(void *arg)
{
return 0;
}
#define LWI_ON_SIGNAL_NOOP ((void (*)(void *))(-1))
struct l_wait_info {
long lwi_timeout;
long lwi_interval;
int lwi_allow_intr;
int (*lwi_on_timeout)(void *);
void (*lwi_on_signal)(void *);
void *lwi_cb_data;
};
/* NB: LWI_TIMEOUT ignores signals completely */
#define LWI_TIMEOUT(time, cb, data) \
((struct l_wait_info) { \
.lwi_timeout = time, \
.lwi_on_timeout = cb, \
.lwi_cb_data = data, \
.lwi_interval = 0, \
.lwi_allow_intr = 0 \
})
#define LWI_TIMEOUT_INTERVAL(time, interval, cb, data) \
((struct l_wait_info) { \
.lwi_timeout = time, \
.lwi_on_timeout = cb, \
.lwi_cb_data = data, \
.lwi_interval = interval, \
.lwi_allow_intr = 0 \
})
#define LWI_TIMEOUT_INTR(time, time_cb, sig_cb, data) \
((struct l_wait_info) { \
.lwi_timeout = time, \
.lwi_on_timeout = time_cb, \
.lwi_on_signal = sig_cb, \
.lwi_cb_data = data, \
.lwi_interval = 0, \
.lwi_allow_intr = 0 \
})
#define LWI_TIMEOUT_INTR_ALL(time, time_cb, sig_cb, data) \
((struct l_wait_info) { \
.lwi_timeout = time, \
.lwi_on_timeout = time_cb, \
.lwi_on_signal = sig_cb, \
.lwi_cb_data = data, \
.lwi_interval = 0, \
.lwi_allow_intr = 1 \
})
#define LWI_INTR(cb, data) LWI_TIMEOUT_INTR(0, NULL, cb, data)
#define LUSTRE_FATAL_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | \
sigmask(SIGTERM) | sigmask(SIGQUIT) | \
sigmask(SIGALRM))
/**
* wait_queue_entry_t of Linux (version < 2.6.34) is a FIFO list for exclusively
* waiting threads, which is not always desirable because all threads will
* be waken up again and again, even user only needs a few of them to be
* active most time. This is not good for performance because cache can
* be polluted by different threads.
*
* LIFO list can resolve this problem because we always wakeup the most
* recent active thread by default.
*
* NB: please don't call non-exclusive & exclusive wait on the same
* waitq if add_wait_queue_exclusive_head is used.
*/
#define add_wait_queue_exclusive_head(waitq, link) \
{ \
unsigned long flags; \
\
spin_lock_irqsave(&((waitq)->lock), flags); \
__add_wait_queue_exclusive(waitq, link); \
spin_unlock_irqrestore(&((waitq)->lock), flags); \
}
/*
* wait for @condition to become true, but no longer than timeout, specified
* by @info.
*/
#define __l_wait_event(wq, condition, info, ret, l_add_wait) \
do { \
wait_queue_entry_t __wait; \
long __timeout = info->lwi_timeout; \
sigset_t __blocked; \
int __allow_intr = info->lwi_allow_intr; \
\
ret = 0; \
if (condition) \
break; \
\
init_waitqueue_entry(&__wait, current); \
l_add_wait(&wq, &__wait); \
\
/* Block all signals (just the non-fatal ones if no timeout). */ \
if (info->lwi_on_signal && (__timeout == 0 || __allow_intr)) \
__blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS); \
else \
__blocked = cfs_block_sigsinv(0); \
\
for (;;) { \
if (condition) \
break; \
\
set_current_state(TASK_INTERRUPTIBLE); \
\
if (__timeout == 0) { \
schedule(); \
} else { \
long interval = info->lwi_interval ? \
min_t(long, \
info->lwi_interval, __timeout) : \
__timeout; \
long remaining = schedule_timeout(interval);\
__timeout = cfs_time_sub(__timeout, \
cfs_time_sub(interval, remaining));\
if (__timeout == 0) { \
if (!info->lwi_on_timeout || \
info->lwi_on_timeout(info->lwi_cb_data)) { \
ret = -ETIMEDOUT; \
break; \
} \
/* Take signals after the timeout expires. */ \
if (info->lwi_on_signal) \
(void)cfs_block_sigsinv(LUSTRE_FATAL_SIGS);\
} \
} \
\
set_current_state(TASK_RUNNING); \
\
if (condition) \
break; \
if (signal_pending(current)) { \
if (info->lwi_on_signal && \
(__timeout == 0 || __allow_intr)) { \
if (info->lwi_on_signal != LWI_ON_SIGNAL_NOOP) \
info->lwi_on_signal(info->lwi_cb_data);\
ret = -EINTR; \
break; \
} \
/* We have to do this here because some signals */ \
/* are not blockable - ie from strace(1). */ \
/* In these cases we want to schedule_timeout() */ \
/* again, because we don't want that to return */ \
/* -EINTR when the RPC actually succeeded. */ \
/* the recalc_sigpending() below will deliver the */ \
/* signal properly. */ \
cfs_clear_sigpending(); \
} \
} \
\
cfs_restore_sigs(__blocked); \
\
remove_wait_queue(&wq, &__wait); \
} while (0)
#define l_wait_event(wq, condition, info) \
({ \
int __ret; \
struct l_wait_info *__info = (info); \
\
__l_wait_event(wq, condition, __info, \
__ret, add_wait_queue); \
__ret; \
})
#define l_wait_event_exclusive(wq, condition, info) \
({ \
int __ret; \
struct l_wait_info *__info = (info); \
\
__l_wait_event(wq, condition, __info, \
__ret, add_wait_queue_exclusive); \
__ret; \
})
#define l_wait_event_exclusive_head(wq, condition, info) \
({ \
int __ret; \
struct l_wait_info *__info = (info); \
\
__l_wait_event(wq, condition, __info, \
__ret, add_wait_queue_exclusive_head); \
__ret; \
})
#define l_wait_condition(wq, condition) \
({ \
struct l_wait_info lwi = { 0 }; \
l_wait_event(wq, condition, &lwi); \
})
#define l_wait_condition_exclusive(wq, condition) \
({ \
struct l_wait_info lwi = { 0 }; \
l_wait_event_exclusive(wq, condition, &lwi); \
})
#define l_wait_condition_exclusive_head(wq, condition) \
({ \
struct l_wait_info lwi = { 0 }; \
l_wait_event_exclusive_head(wq, condition, &lwi); \
})
/** @} lib */
#endif /* _LUSTRE_LIB_H */
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